How to properly cut a log on a band sawmill. The work of the band sawmill: sawing logs into boards. Band sawmill Taiga T3 and its features How to saw boards on a band sawmill table

Planks and beams are one of the main building materials. But not everyone has the financial ability to buy ready-made boards. In such situations, one of the solutions is to independently engage in timber harvesting on a plot taken in the forestry.

The advantage of a chainsaw as a sawing tool

You can cut a log using a sawmill, a petrol or electric saw and additional devices. When choosing one of these tools, consider the amount of work to be done. The cost of the cheapest stationary sawmill together with all the accessories is 150 thousand rubles. The chainsaw is much cheaper. It is more convenient than an electric saw for the following reasons:

• Electricity is not required to operate the tool - this makes it possible to use the chainsaw on plots.
• More powerful than an electric saw.
• Starts smoothly and allows convenient speed control, which reduces the chance of chain breakage.
• The overrun brake responds faster than a saw.
• Long working time without interruption - up to one hour.
• Can be used in high humidity conditions.

Types of working attachments

When sawing logs with a chainsaw, various attachments are used.

• Rip saw attachment. It is used for sawing a log lengthwise, the process takes place in a horizontal position. After work, the master gets the same thickness for the product. The finished materials undergo a drying process, after which the boards are used in construction. In appearance, the device is a frame small size, it is attached to the bus on each side.

• Drum debarker (gummer). With the help of such a nozzle, it is easy to dissolve the log, it works due to the V-belt transmission. It is attached to the belts on both sides using special pulleys. The speed of rotation of the shaft depends on the size of the pulleys, so the performance of the nozzle is easy to change. This technology forces the master to carefully monitor each stage of the process; some specialists use an assistant during this cut. But this option requires increased security measures.
• Sawing with a lightweight nozzle. The method is not very efficient, but it is used quite often. The element is fastened on one side, but the workpieces are slightly uneven. Such materials are required for building barns or fences.

Features of sawing with a homemade tool

You can easily cut a log into planks using a self-made tool. It is not difficult to make it. To do this, follow these steps:

• As a support, you need to use a frame from a school desk or a pipe with a cross-section in the form of a square, its optimal size is 20x20, and more is allowed.
• It is necessary to build two clamps, at one end mount a cross member with two holes for tie bolts, make a projection for the bus in the middle.
• For longitudinal sawing of logs into boards, you need to make a support frame, its width should be seven to eight centimeters less than the length.
• Then, two parts ten centimeters long are welded to both sides, holes for bolts are made, a handle is attached in the middle for ease of operation.
• Then you need to insert the clamps into the grooves, install the bus, fix everything carefully.

It is not difficult to work with a homemade tool, for this you will need goats, they will serve as a support. In addition, you need to prepare a metal rail or board to use as a guide. A log is laid from below, the required height for work is set.

The order of the preparatory work

To cut a log lengthwise, you need to perform the following sequence of actions:

• Take two straight boards and attach one to the other at right angles. The result is a solid flagship line.
• To support the made ruler, you need to make stops from the boards.
• The movement of the trunks must be carried out using a turner.
• The log should be placed on a comfortable base.
• On the tire of the chainsaw, using nuts, you need to fix the frame.
• Lead ruler supports must be attached to the ends of the log, checking the horizontal position with a level.
• Self-tapping screws must be used to fix all brackets and structural elements. Nails are not suitable for these purposes, since they are difficult to remove in the future without causing damage to the structural parts.
• The guide ruler must be attached to the supports using brackets and its height must be adjusted so that the cut will not go along it, but approximately one centimeter higher.
• The log must be rotated and the second plank must be secured in such a way that it rests on the ground and supports the log.

The order of the main work

• Now you need to start the chainsaw and make the first cut.
• Next, you need to free the log from stops and boards and attach a leading ruler on the cut surface of the log in the direction of the next cut. The ruler is attached directly to the surface or to the ends of the log using supports. The second cut is made perpendicular to the first cut.
• The log must be turned and secured with a board point-blank to the ground.
• You do not need a leader ruler for further actions. One of the trimmed sides serves as a guide.
• It is necessary to adjust the thickness of the cut on the frame and saw off the log from the other side in such a way that you get a bar with bark left on only one side.
• This bar must be turned over and fixed in such a way that the attachment point of the fixing board is as low as possible.
• Then you need to adjust the frame to the required thickness of the board and cut the timber into boards.

Safety rules when performing work

• Do not use a circular saw without a protective cover.
• Wear headphones, gloves, goggles, heavy clothing and a respirator.
• Fuel should not be poured into the hot tank of the instrument; you must wait until it cools down.
• Children should not be allowed at the work site.
• The tool must be started on the ground with the chain brake engaged, which must only be released before starting sawing.
• You should always have a first aid kit on hand.
• When working, you need to hold the chainsaw by the handle of the arc, moving it forward along the guide. You should not press on the chainsaw with great effort - it should move freely.
• Right-handers should place the log on the right side of themselves, left-handers on the left.

Professional advice

1. GENERAL INFORMATION ABOUT THE MACHINE

The horizontal band saw machine is used for sawing wood of any hardness on boards, beams, laths. Sawing occurs by moving the saw frame with a cutting tool (band saw) along the stationary rail guides of the band sawmill.

The use of a band sawmill allows:

• produce boards with high surface quality from material
• get a board with an accuracy of 2 mm. with a length of 6 m;
• band sawmill reduces waste by 2-3 times,
• reduce energy consumption;
• quickly adjust the cutting size,
• The band sawmill is capable of sawing short workpieces (from 1.0 meters) and producing products up to 2 millimeters thick.
• the band sawmill operates in the conditions of UHL 4 (GOST 15150-69). The band sawmill is equipped with an electromechanical-type saw unit hoist.

2. "Band sawmills" - work and device:

2.1 The main units and parts of the band sawmill:

• A bed that moves along the rail guides in the horizontal direction;
• Saw frame;
• Raising the saw frame;
• Electric cabinet;
• Clamping a log;
• Movable slider of the driven pulley;
• Driving pulley;
• Driven pulley;
• V-belt transmission;
• Rail guides of the band sawmill;
• Tensioning mechanism for the band saw;
• Saw band mounting connector;
• Belt sawmill pulley cover
• Coolant tank
• Saw guide fixed
• Saw guide movable

The frame of the band sawmill has a U-shape and soles with rollers for moving the saw frame on the rails and felt brushes that clean the guide from sawdust. The saw frame is lifted by two sliders located on the frame racks. The movement is carried out by a two-way, synchronously connected chain transmission driven by an electric motor through a gearbox.

The frame is made of two channels, which are located in parallel and interconnected. On one end of the frame, a leading saw pulley is fixedly fixed, on the other, a driven one that can move longitudinally. Saw band sawmill tensioned by a spring-screw mechanism, the spring dampens the thermal expansion of the saw band. In the manufacture of a band sawmill, the tension is calibrated for a saw with a width of 35 centimeters. Risks on the tensioner body and washer are equal to a pulling force of 525 kilograms. In the front beam of the band sawmill and on the slider of the driven pulley, there are two locks for removing and installing the saw band. On the brackets located in the middle of the frame, there are two band saw guides (movable and fixed), which are equipped with support rollers and an adjustment system and a bar. The torque is transmitted from the sawmill engine to the drive pulley by a V-belt transmission. The coolant reservoir is mounted on top of the saw blade guard. The fluid supply is regulated by taps located on the tank. The control panel for the band sawmill is located on the upper lintel of the machine.

Collapsible guides of 3 sections, which is convenient for transportation. Underneath there are support plates into which the anchor bolts are screwed. On top of the guides of the band sawmill support the logs. The log is fixed on rail guides with four screw clamps and a stop that provides 90 degrees.

3. ADJUSTMENT OF THE SAW PULLEYS

3.1. The machine provides for the adjustment of the position of both pulleys in relation to each other in the horizontal and vertical planes. It is necessary to achieve that the band saw with a tension of 6-8 kg / mm2. in section, it did not leave the rims of the saw pulleys by one branch.

3.2. First of all, the pulleys are adjusted in vertical planepositioning them at right angles to the saw frame. To do this, a bolt Ml0 is screwed into the slider of the driven pulley from below to its axis, and on the driving pulley, adjustment is carried out by installing spacer washers or plates. This operation is performed by the manufacturer.

3.3 To adjust the position of the saw pulleys in the horizontal plane, two bolts Ml2 are screwed in at the ends of the frame on the side of the drive pulley, and one to the axis of the driven pulley.

It is necessary to adjust the pulleys of the band sawmill in the following sequence:

3.3.1 Switch off the automatic power supply at the control panel.

3.3.2 Open the saw pulley guards.

3.3.3 Install the saw band on the pulleys so that it protrudes beyond the edges of the pulleys by the amount of the tooth height plus 2-5 mm.

3.3.4 Close the movable connectors (locks).

3.3.5 Tighten the band saw by turning the tensioning nut by the value that is optimal for the type of band saw (based on 6-8 kg / mm2).

3.3.6. Rotating by hand for the driven pulley in the direction of sawing (counterclockwise) it is necessary to watch what position the band saw will take on the pulleys. If the tape runs out by an equal amount from both pulleys, then without loosening the saw tension, release the Ml6 lock nut that secures the driven pulley axle to the saw frame (saw frame slider).

3.3.7 Then loosen the M12 locknut and screw in the Ml2 bolt a small amount, then tighten the M12 locknut and the M16 locknut.

3.3.8 Repeat point 3.3.6 and if the tape runs off, repeat the adjustment until the correct result is obtained.

3.3.9 If the band runs inward evenly, release the tension on the saw band.

3.3.10. Loosen the Ml6 lock nut, M12 locknut and unscrew the M12 bolt a small amount, then tighten the M12 and M16 nuts.

3.3.11 If the belt is in position according to the instructions, then the adjustment is done correctly.

3.3.12 If the band saw immediately escapes from the drive pulley when rotating, then the adjustment should be started with it.

3.3.13 To do this, depending on the direction from the belt running (outward or inward), release the left or right Ml6 lock nuts and make the adjustment in the same sequence as on the driven pulley.

3.3.14 After adjustment, tighten all nuts.

3.3.15 Close the saw wheel guard doors.

3.3.16 Switch on the automatic email feeder. energy on the control panel.

3.3.17 Briefly switch on the saw pulley drive and make sure that the saw band is in the correct position. The machine is now ready for use.

4. REQUIREMENTS FOR SAW BANDS

1. During the operation of the band sawmill, in order to increase the service life of the band saw, it is necessary to make the correct tension on the pulleys.

1.1 The amount of tension, depending on its width, is determined by the "Tensometer" device.

1.2 Attention! The band saw should not be in operation for more than 2 hours. After this time has elapsed, it must be removed from the machine and hung out in a free state for at least 24 hours to relieve fatigue stresses.

2 Use the correct band saw blade lubricant.

As a cutting fluid (coolant), in most cases, just water is enough, or water with the addition detergent ("Fairy", etc.). However, at low temperatures it is best to use a mixture of 50% -80% diesel or kerosene and 50% -20% engine oil or oil for lubricating chainsaw tires. The use of turpentine also gives good results when sawing softwood.

If water is used as a coolant, it is necessary to wipe the pulleys and belt with oil at the end of the work.

3. Always release the tension on the saw band.

When you're done, release tension on the saw. During operation, the blades heat up and stretch, and then, as they cool, shrink to tenths of a millimeter during each cooling period. "Therefore, the belts left on the pulleys under load overload themselves, and they form an imprint from the two pulleys, which causes cracks in the cavities between the teeth.

4. Use the correct set of teeth.

The divorce is correct if you have 65-70% sawdust and 30-35% air in the space between the saw blade and the processed wood. If your set is too large for the weight or thickness of the wood, there will be too much air and not enough sawdust in the kerf. You will have excessive sawdust losses, and as a result, a large roughness of the processed wood. If the dilution is insufficient, you will not get enough airflow to remove the sawdust from the cut. Hot sawdust is a sign of this. This can do the most damaging damage to the saw: working intervals will be short and the saw will fail prematurely. The sawdust should be cold to the touch. And finally, if there is insufficient set and the wrong sharpening angle, the saw will cut a wave on the board. From our point of view, you cannot work with the same set of tines with logs of different diameters, timber and bar.

You have to sort the timber.

For every 20-25 centimeters increase in size, it is necessary to increase the routing by about 18%, depending on whether the wood is hard or soft, wet or dry. The only way to achieve the desired layout is to make control cuts on a specific log. Increase the setting by 5-8 hundredths of a millimeter on each side until the teeth marks are visible. This means that you are working with 50/50 mixed air with sawdust. After that, reduce the tooth setting by 8-10 cents on each side, and you will achieve the desired result. Please note: You should only breed the top eighth of the tooth, not the middle or bottom. You don't need to fill the gap between the teeth completely when cutting. When you work with softwood, whether wet or dry, the chips increase in volume 4 to 7 times their cellular state. Hardwoods, wet or dry, increase in volume only 1 / 2-3 times. This means that if you are sawing 45 cm pine logs, you will need to set the teeth 20% more than when working with 45 cm oak logs. Always set your teeth apart before sharpening.

5. Sharpen the saw correctly.

There is only one way to sharpen band saws. The stone should travel down the surface of the tooth around the base of the cavity and up along the back of the tooth in one continuous motion.

The space between the tines (gallet) is not a sawdust bin. The power flow of air, cooling of steel and removal of sawdust depends on it.

If you have the correct set of teeth, air is blown along the log at the same speed as the saw, as a result sawdust is sucked into the galllet. The sawdust cools it significantly by passing around the inside and outside of the next tooth. The space between the teeth needs to be 40% filled to provide adequate cooling and increase saw run time.

6. Install correct angle sharpening.

Thanks to the deep gaiters, we can use reduced sharpening angles that transfer less heat to the tip of the tooth. The series of belts use a 10 degree hook angle which is capable of penetrating most medium hard to medium soft wood surfaces.

The general rule is that the harder the wood, the smaller the sharpening angle.

Caution: Don't trust the scales and rulers on your sharpener!

The pins and guides on it wear out. In the process of work, the profile of the stone changes.

Use a protractor to check the correct sharpening angles. Attention; we recommend changing the saws every two hours of continuous operation, while allowing them to rest for at least a day.

During the operation of the machine, it becomes necessary to regulate individual component parts in order to restore their normal operation.

In fig. 1 shows some parameters of the canvas, which determine its durability and performance where:

A - sharpening angle, this is the angle between the front surface of the tooth and the plane perpendicular to the back of the saw; B - cavity of the tooth; C - posterior surface of the tooth;

E - divorce, this is the deviation of the tooth from the vertical. The divorce line (the place of the bend of the teeth) is at a distance of 1/3 from the top of the tooth; R is the radius of the cavity;

Р - tooth pitch, this is the distance between two teeth; H is the height of the tooth, this is the distance from the base of the tooth to its top.

Dependences of saw parameters on the type of wood
Wood type	Saw parameters
	Sharpening angle	Minimum height tooth, mm	Divorce size, mm
Soft hardwood	12-16	4,8	0,54-0,66
Soft conifers, medium resinous	12-16	4,8	0,52-0,66
Soft conifers, high resin content	12-15	4,8	0,52-0,60
Hardwood	8-12	4,5	0,41-0,46
Soft hardwoods, frozen	8-12	4,5	0,46-0,56
Soft conifers, medium resinous, frozen	8-12	4,5	0,46-0,56
Soft conifers with high resin content, frozen	10-12	4,8	0,41-0,51
Hardwood, frozen	8-12	4,5	0,41-0,46

Problems that arise and their solutions

Possible reasons	Remedies
Cracks in the cavity of the tooth
Big feed
Incorrect belt tension	Set tension according to manufacturer's recommendation
Small corner radius	Increase radius
Small pulley diameter	Install the saw of the appropriate thickness
Overheating of the tooth and interdental cavities	Correct grinding wheel, adjust feed when sharpening
Overheating of the saw band	Increase the setting of the saw, hang the saw in the "inverted" state after every two hours of operating time
Incorrect wiring	Check the layout, correct it according to the recommendations for the hardness of the cut wood.
Incorrect rake angle selection depending on wood hardness	Change the rake angle according to the recommended hardness of the wood being cut.
Dull saw teeth	Sharpen
Belt wear on pulleys	Check the technical condition of the pulleys and the tension of the saw band
Incorrect installation of rollers (dampers)	Install the rollers according to the recommendations of the machine manufacturers
Wear of the working surface of the rollers (dampers)	Replace
Imbalance of 1 pulleys, wear of the working surface of the pulleys	Perform pulley balancing and equipment maintenance
Installing pulleys in more than one PLANES	Adjust the position of the pulleys
Cracks on the "back" of the saw
Incorrect belt tension	Set belt tension according to manufacturer's recommendations
Big feed	Reduce feed (feed must be uniform)
Runout of pulleys, installation of pulleys not in the same plane	Eliminate runout adjust pulleys
Vibration of pulleys	Replace bearing units, check balance
Improper installation or contamination of the idler rollers	Install according to the manufacturer's recommendations, clean
The width of the guide rollers does not match the width of the belt	Install the belt of the required width or replace the rollers
Saw operation without rest, without removing the blade tension	Follow the manufacturer's recommendations. Release the belt tension at the end of work
Thickness variance of the obtained materials, ribbon wave (wave)
Incorrect wiring (different wiring on the sides of the tape)	Make wiring according to recommendations
Roller wear, bearing failure	Replace
Burr on the side	Reduce sharpening feed. To produce
belt surface after sharpening	deburring (nursing after sharpening)
Insufficient cutting speed	Reduce feed or increase cutting speed
Incorrect belt tension	Install according to manufacturer's recommendations
The installation of the tape is not in the same plane with the material being cut (as a result, the reduction of the set of teeth on one of the sides)	To produce correct installation ribbons
Overheating of the tape	Produce cooling, saw rest
Incorrect installation of rollers (dampers)	Install the rollers according to the manufacturer's recommendations
Big feed	Reduce
Loose, material to be cut	Anchor

5. PREPARATION OF THE MACHINE FOR WORK

5.1 Before work it is necessary:

• check the reliability of fastening of parts and the tightness of all threaded connections; lubricate the rubbing parts according to section 7;
• check the installation of the saw band and, if necessary, adjust its position on the saw pulleys in accordance with section 3;
• to ensure a stable position of the saw in the log at the time of sawing, as well as align the band in the cutting zone and prevent it from coming off the pulleys under excessive load, install the support rollers of the movable and fixed guides of the band saw so that they press the saw band down. In this case, the deflection of the tape should be 2-5 mm. Then bring the felt bar to the saw band. To reduce the belt deflection arrow, move the movable guide at a distance of 50-150 mm from the side surface of the wood;
• in order to avoid flaring of the rear edge of the belt and subsequent wear of the plane of the pulleys, adjust the support rollers so that there is no constant contact of the belt with their stop edge. The gap should be 3 mm. using a level and a flat grinded pad to avoid touching the saw teeth, check the horizontal of the band saw, adjust if necessary;
• the adjustment of the guide rollers in the vertical plane eliminates the twisting of the saw in working area;
• check the tightness of the band saw guard and V-belt drive.
• Make sure that the surfaces of the saw band and saw pulley rims are clean and that the scrapers are firmly against the wheel rims.
• turn on the electric motor and make sure that the band saw is moving normally and correctly;
• when sawing, it is imperative to use coolants for cooling and lubrication (kerosene or diesel, diluted in half with machine oil, see section 4). The coolant is poured into the tank;
• the reverse (idle) movement of the machine is to be carried out by first lifting the saw band above the plane of the log (by pressing the "up" button on the control panel) by 10-15 mm.

6. MAINTENANCE

When maintenance it is necessary to tighten the fasteners and, if necessary, change the grease in the bearings, measure the insulation resistance for electric strength.

The following adjustments must be made during operation:

• the tension of the drive belts, which is ensured by the tensioning screw of the electric motor with the previously loosened bolts and subsequent tightening; (ATTENTION! Do not overtighten the belts, thereby increasing the load on the bearings).
• saw band tension adjustment;
• parallelism adjustment of the saw pulleys!
• sharpening the teeth of band saws (it is recommended to sharpen corundum wheels of a flat profile (n) with a grain size of 16-25 on a bakelite (b) bond with hardness C1 (C-medium hardness, 1-volume abrasive content 60%) or CT1 (medium hard). 6-8 mm. Good quality is provided by the peripheral speed of rotation of the circle 20-25 m / s. To lubricate the bearings, use the grease "Litol-24." Change the grease after four months when working in one shift.
• replacement of worn out scrapers:
• every shift to impregnate felt scrapers-brushes with working off, salary, etc.

7. INDICATION OF SAFETY MEASURES.

The machine is made in accordance with the safety requirements of GOST 25223, GOST 12.2.026.0, and GOST RMEK602041.

The machine must be properly grounded during installation. For this, there are grounding lugs on the foot of the frame, as well as on the rails of the track.

When using the machine, you should regularly, but at least once a week, clean the electric motor and electrical equipment from dust and dirt. The presence of moving parts and electrical equipment in the machine requires strict adherence to safety rules during its operation.

When working on band sawmill - be sure to observe the following rules:

• monitor the health of the insulation of conductive cables and the reliable connection of their ends;
• check the integrity and reliability of grounding wires;
• make adjustments, replace the band saw and troubleshoot with the obligatory disconnection of the machine from the mains;
• in case of a band saw breakage or a power outage, the machine must be immediately disconnected from the mains;
• when working on the machine strangers, as well as the operator of the machine should not be in the working area, as well as near the nozzle for ejection of chips, because in the event of a break, the band saw can slip out in this direction;
• do not work on the machine with the doors of the saw pulley covers open;
• do not open the doors of the saw sheave covers until they come to a complete stop;
• you cannot work under the saw frame of the machine without first substituting a solid support under it;
• do not cut a log that is not attached to the tracks.
  

The quality of the machine's operation, in addition to those factors that are indicated in the passport (correct adjustment of the saw pulleys, correct setting and sharpening of the saw teeth), the quality of the rail track installation plays an important role. So, with poor-quality installation, various defects can be observed on the layer of the material being cut, namely, "waviness" of the surface, "taper", "steppedness", "non-parallelism", etc.

The rails are leveled in the transverse and longitudinal directions. For normal operation of the machine, a solid foundation is required.

In this case, the straightness of the rail guides is checked using a thin cord and a ruler. Steel gaskets of different thicknesses are placed under the plates and finally attracted them to the foundation.

When correct installation and careful handling of the machine, the company guarantees high quality of the wood material being cut, the deviation in the thickness of the cut at a length of 6 meters is no more than 2 mm.

9. MACHINE MALFUNCTIONS, THE CAUSES OF THEIR APPEARANCE METHOD OF ELIMINATION

Malfunctions	Reasons for the appearance	Remedies
Saw vibration in the cut	Poor welding quality and stripping of the joint	Digest and clean up the weld
	Runout of saw pulleys	Renovate
	Sawdust sticking to pulleys and belt	Clean after removing the saw. Adjust scrapers and coolant supply
Saw band slipping off the pulleys	Pulleys not adjusted	Adjust the pulleys according to item 4
	Weak saw band tension	Adjust the tension of the saw band
	Saw band guides incorrectly installed	Adjust the saw band guides
Saw band break	Excessive saw band tension	Adjust tension
	Incorrect use of the saw band	Monitor sharpening and routing, remove the tape from the machine every 2 hours and hang it up for "rest" and release of internal stresses according to the recommendations of the manufacturers, release the saw voltage during short and long breaks in work.
	Too much feed force	Reduce feed rate.
	Sawdust sticking to the tape when working with conifers	Adjust scrapers and lubricant supply.
"Wavy" cut, not parallel to the cut surface to base surface of the workpiece	Insufficiently installed rail track, not all supports are placed on the site	Align the track correctly
	Saw drift up or down due to incorrect set of teeth	Spread the teeth correctly
	Dullness (rounding) of tooth tops	Sharpen the band saw
	Erroneous acceptance of a not sharpened and not set new saw as fully prepared for work (belts supplied in coils with manufacturing plants come with sharpened teeth from under the stamp, but not sharpened and not set).	Sharpen and correct the new saw blade
	Large sag of the band when cutting due to improper installation of the left movable roller.	Install the left roller 50-150 mm from the side surface of the wood

CUTTING BIRCH

The main idea behind sawing birch correctly is the ability to cut as many side boards as possible from a log.

To increase the yield of high-quality sawn timber, we recommend using only the butt part as raw material (the first cut, 2.5 / 2.8 or 3.1 meters long), with a diameter of at least 26 cm, in the presence of a false core, no more than 1/3.

On a band sawmill, birch is sawn only with the rotation of the log on 90 0 or 180 0 .

Sawing (sawing through a half-bar) by rotating the log 180 0

Sawing logs on a band sawmill with the rotation of the log on 90 0

1. The croaker is removed

(until a layer is obtained with a width of at least 110-115 mm.);

2. Unedged board No. 1 with a thickness of 28 mm is removed;

3. In the presence of defects or a false core on the lower face of board No. 1 in an amount exceeding the permissible for grade 2C, the log is rotated on 90 0 ... Board No. 2 is removed. In the absence of defects, an additional board is removed.

4. In the presence of defects or a false core on the lower face of board No. 2 in an amount exceeding the allowable for grade 2C, the log is rotated on 90 0 ... Board No. 3 is removed. In the absence of defects, an additional board is removed, etc.

After removing all the side boards, a 110x110 mm beam remains. or sawn into boards with a thickness of 30 mm with a fixed width for grade 3C (110/135/165)

1. Place the set on a semi-beam with a thickness of 110, 135 or 165 mm., Depending on the diameter of the false core, edge boards 28 mm thick.

2. The semi-beam is sawn into edged boards 28 mm thick.

Unedged boards are sawn on an edging machine with the maximum possible width without a fixed gradation or in a size in width of 110/135/165 mm.

Sorting birch lumber

Birch lumber is sorted for two main markets: America and Europe

Grade 0 -Select - America orA3 - Europe

One plank of this class must be free of knots and other wood defects.

On the other side, knots are allowed every 1 m.

________________________________________________________________________________

Grade 1 -Common 1 (1 Common) - America or AB - Europe

On both sides of the boards there may be knots every 1 m. In length.

___________________________________________________________________________________

Grade 2 - BB - Europe

Any number of knots is allowed on both sides of the boards. a spurious kernel is not allowed.

Grade 3 - ВС - Europe

In grade 3, the number of knots is not limited on both sides.

False kernel on one side without limitation.

If the false core is from 2 sides, then no more than 50% of the board width

Marriage

false core (red core) on both sides more than 50% of the width

center board with core tube

The road to prosperity for your sawing business

Wood is a multi-purpose material. Although wood is abundant in Russia, we still need to make sure that we do not waste this valuable natural resource, when we turn it into lumber, and when we turn lumber into furniture, houses and other useful things.

Remember: only wood should be cut good size... Your plans should be to cut as much high quality lumber as possible from this tree. You try to do this with the least amount of waste and at the same time, you want to achieve the high value and usefulness of the product you make. How to do it?

Raw material quality

The efficiency of sawing depends on knowledge about the quality of logs. It is very difficult to get good lumber from crooked, knotty logs of small diameter. Therefore, the first step, even before you start sawing, is to evaluate and sort the logs according to their quality.

Sorting is carried out depending on appearance logs. The main criteria are diameter, curvature, knots and the number of false cores. A log is considered to have four faces, each face being 1/4 of a circle and occupying the full length of the log. These four faces do not overlap. A clean edge is free of knots, bark scars, cracks, chips, rot, insect damage, etc. The cleaner the edge, the higher its value, and the higher the quality of the lumber produced from a given log.

We have data on sawing thousands of cubic meters of wood. Based on these data, it is possible to estimate the volume (total and by grade) and the cost of sawn timber produced from logs different sizes and varieties.

Curved small diameter logs produce less valuable lumber than straight and large diameter logs. Therefore, when choosing raw materials, you should buy logs with a diameter of at least 26 cm in the upper part, of the optimal length and with the least distortions.

Logs used for sawing must be properly stored. In warm weather, they can deteriorate within a few weeks. It is best to start working on the tree as soon as it is cut down. The ends of the logs will immediately begin to dry out, and, as a result, the wood here will first change color, and then cracks will appear. For several months of storage, cracks can penetrate into the log by 15-20 cm, and the delusion spreads up to 1 m. from the ends to the depth. In addition, dry ends are difficult to cut. In such a material, the saw gives a wave and boards of variable thickness are obtained.

Sawing

Getting started is the key to getting the most profit and the most useful, good quality lumber from every log. The sawmill must keep in mind the full range of potential products needed to manipulate the log to maximize yield. This requires a sixth sense or even "X-ray" vision - you need to "see" what is inside the log before sawing.

For the sawman to work efficiently, he must receive logs that have been felled and stored properly. The logs should not have large bulges, bends, dirt and cracked, bursting ends. The ends of the logs should not be dry. In short, the sawman is not a magician: the way the trees were cut, cut to length, and sorted before sawing affects the potential volume of the lumber.

To optimize production, the sawmill must consider how the lumber will be trimmed. If the sawmaker is not involved in trimming, then the trimmer and the sawmaker must closely communicate with each other, exchange experience. They need to work as a team. At a minimum, these people should be able to match the required plank dimensions with the current volume of wood.

Clean, knot-free, most valuable wood is found on the outside of the log. The quality decreases as you start sawing closer to the center of the log. The most valuable are wide, long, clean boards.

Sawing methods of wood

Which sawing operation to use (the sawing operation includes decisions on board thickness, log flipping and compensation for log taper) depends on many factors: the type of wood, the quality of the log, its size, the design of the machine and the grade of lumber to be obtained. There are 3 standard cutting patterns.

Circular sawing
A cut is made, and the log is turned over to a new face, sawed and turned over 90 or 180 degrees again, until the central part of the log remains. From a financial point of view, it is the best way for medium to high quality logs, although on some sawmills it is difficult to carry out such a turn of the log, and the daily productivity will be low. Of course, a hydraulic machine solves this problem.

Simple sawing (or camber sawing)
The log is sawn into unedged boards without flipping to the end. While this may be the quickest and easiest method of sawing, each board needs to be cut off the sides. In addition, the lumber cut in this way is of inferior quality, has a lot of waste and is extremely prone to cracking at the center boards. In short, sawing "to collapse" is justified only in the case of logs of very low quality, when all of the above disadvantages are no longer particularly important.

Sawing timber
In this case, the log is cut at first as when sawing in a circle, but the central part of the log can have any dimensions, or is transferred to another machine for processing along the technological line. Sawing cant maximizes productivity sawing machine... Mostly in this way, logs of medium and low quality are sawn, when it is impossible to get valuable lumber from the log. This saves time and effort in producing a product of not very high quality and therefore not very high price.

First cut

Of all the challenges the sawmill faces, deciding which side of the log to cut from (and therefore which cutting surface to open first) is the most important. (As already mentioned, we divide the log into 4 faces, each of which extends along the entire length of the log and takes 1/4 of its circumference). The choice of the first face is determined by the position of all the others. Before sawing begins, a log can be sawed in a million ways, but only a hundred of them will really benefit! With the decision to cut the first cut, the sawman only has a few thousand other decisions to make.

In the case of circular sawing and cant sawing, two basic rules apply.

Rule 1. The worst edge of the log is cut first, regardless of the taper of the log. (Allowing for runaway means raising or tilting the log so that the saw is parallel to the bark.) Since this is the worst part of the log, it will make short boards and a lot of slab. Since we do not take into account the taper of the log, this allows us to cut parallel to the bark from the opposite, better side of the log, without lifting or tilting the log. This means that more high quality boards will come out of this best part of the log, moreover, the same length as the length of the log.

Rule 2. Saw the best edge of the tree first, taking into account the taper of the log. This means that the log must be lifted or tilted so that the first cut is parallel to the bark.

The end result of both methods will be roughly the same, but the second method has one advantage: it makes it easier for the sawman to position the log (i.e., rotate it) because the open edge is the cleanest and free from defects. In the case of rule 1, the best part of the tree is the opposite of the open edge. It is not visible, and it is impossible to accurately position the log. Generally, if the wood is of good quality, rules 1 and 2 work pretty much the same way. However, if you run into a worse log, take rule 2 into service.

Large, high-quality logs (these are logs from the lower, butt part of the tree) provide the most valuable lumber.

Remember, you won't make money just by sawing boards - the boards still need to be sold. For this reason, the critical factor for you is not the sawing process itself, but the product - its grade, value and utility.

If the log is good, it is at least unwise to produce large lumber and railroad ties. Because the price of a timber is always less than the price of a board.

For taller logs, circular sawing is recommended. In fact, tapering sawing (ie, tilting the log so that the cut is parallel to the bark) is recommended for all "good" edges. The result will be clean timber along the entire length, more valuable pieces of lumber. When you get to the low grade part of the log, go to the shape of the log and minimize the trimming operation on the sides.

From logs of small diameter, from which it is impossible to obtain a wide and knot-free material - the profit is very small, or none at all. This means they need to be cut as quickly as possible. Any sawing method works here. Most often they are sawed into a bar (this is good from a financial point of view), or they are simply sawed “into collapse”. Remember that every minute of sawing costs money, therefore a trade-off must be found between the cost of production and the price of the final product. In this case, it is generally better to reduce the flips of the log to zero.

Logs with small diameters from 16 to 22 cm give such an insignificant profit that it is better not to deal with them at all. Invest money in good wood, instead of rushing into the cheap - my main advice.

Large diameter logs are a real challenge for the sawmill. I say this because such logs can produce a significant amount of good lumber, and here a lot depends on the sawman how he will turn the log. Here the decision to rotate the log is critical for profit.

To begin with, the sawman uses Rule 1 to choose the worst part of the log and cuts it down without considering the run. But don't cut too much on this side. For small logs, you generally need to cut one board and then turn the log to the opposite side.

Another way is for the sawman to use Rule 2 to choose the best side of the log and start cutting based on the taper of the log. Then this part is sawn for a long time before the log is turned over.

Flip log

The lumber is cut from one side until the sawman expects the next board on that side of the log to be as good as the boards that can be obtained from the other side. (Exception: if you start sawing from the worst edge of the log, then cut until you have a perfectly smooth cutting surface to flip the log onto.) In other words, the good side of the log needs to be sawed deep, and on the bad side, the slab or slab and one board are simply removed.

Usually, when sawing, the log is flipped 180 degrees. Since many sawmills do not have log-turning devices, the benefits of rotation need to be discussed in detail.

When sawing with a turn of 180 degrees, we get several unedged boards, which need to be additionally trimmed on the sides, and the half-beam cut into ready-made edged boards. When flipped 90 degrees (always turning to an adjacent edge), we get unedged boards and additionally several half-edged boards that need to be cut on one side. This circumstance alone can already be a significant argument in favor of turning the log 180 degrees, especially for small businesses. In addition, this method of sawing produces more wide planks, which are usually more valuable. However, if the edger has only one saw, the 90 degree flip sawing method may be more convenient.

In addition, flipping to an adjacent edge at a sawmill with manual log tilting can be more difficult due to the need to accurately "catch" the angle of 90 degrees, and from an economic point of view and in terms of cutting speed, rotation of the log by 180 degrees is more advantageous.

After the two opposite edges of the log have been sawn, you need to move on to the third and fourth. Usually the worst of these edges is cut first, without considering the taper of the log. However, a good quality edge should always be cut parallel to the bark to maximize the yield of good lumber from the log.

With any overturn of the log, the internal stress of the wood is relieved, which, as a result, avoids bending of the log, crevices and cracks.

Deciding on the size of the lumber

The width of the first plank is critical when sawing from all four sides of the log.

Good quality edge
If the sawman thinks that the first board cut can be classified as good grade, then the minimum width of the sawn timber should be 11 + 1 cm. Why? Because the board of natural moisture should have a width of at least 11 cm.To take into account the further processing of the board (trimming on the sides), it is recommended that 11 + 1 cm, and not 11 cm, but still it is not recommended to specially produce a lot of this size, because the quantity narrow boards per lot is limited.

Definition of variety

Since our company is focused on exporting sawnwood to the United States, there are five main types of hardwood in their market:

FAS, Select, 1 Common, 2 Common and 3 Common. Let's briefly characterize these varieties:

FAS means lumber that is at least 85% clean on 4 sides. Clean means no knots, rot, loose core, cracks, wane, stains and other defects. The clean surface should be ample in both the length and width of the lumber. The size of the lumber in this case is not less than 165 mm. x 2.45 m.

Select - this is actually the same as FAS, but one face of such lumber can be like grade 1 Common. In this case, the size of the lumber is at least 11 cm x 2.15 m.

1 Common - clean from the worst edge by at least 70%. (no more than 1 knot per 1 meter of length). The size of the lumber in this case is at least 11 cm x 1.85 m.

2 Common - only 50% clean on the worst side (no more than 2 knots per meter of length)

3 Common - this is lumber, which on the worst side is only 33% pure.

Of course, this is only a general description of sorting. In fact, there are rules issued by the American Hardwood Association (NHLA rules) that explain in detail individual cases.

Currently, US buyers are limited to only two varieties -

this grade Select & btr... - a mixture of FAS and Select grades

and grade 1 Common

The rest of the material, of lower grades, is in demand among European buyers.

findings

• Sawing logs can be profitable businessif done wisely and safely.
• The storage of logs in the warehouse should be as short as possible.
• The logs must be protected from drying out from the ends.
• Logs should be cut from the worst edge without compensating for the taper of the log, or from the best, but taking into account the taper of the log.
• Logs need to be flipped on the bed every time the other side of the log promises to produce better quality boards than the one you are currently sawing.

All photos from the article

Sawed logs are boards,. The task of competent and efficient sawing of trunks is extremely important for independent or industrial logging, in addition, knowledge of the basics will help you choose the right timber.

We will cover the main points related to this topic and show you how to properly saw a log on a band sawmill.

Sawing logs

The main task

Important! The sawing scheme is selected in accordance with the quality of raw materials, the purpose of the board and the capabilities of the equipment.

Sawing tool

Logging is done using a special tool. For normal work by today's standards, you need a special machine for sawing logs with your own hands, which is called a sawmill.

Sawmills are of two types: disk and tape. Disk use circular saws and are considered less effective, since they have a greater cutting thickness (from 6 to 9 mm), less precision and depth.

The band sawmill is equipped with a different system: the saw is a band put on rotating rollers. The cutting thickness is approximately 1.5 - 3 mm, which is quite economical in terms of chip rejection.

Modern models are distinguished by high accuracy and productivity of work, they are automated and have a tilting mechanism for lifting and turning over logs in the case of circular sawing or sawing a bar.

With the help of a chainsaw, you can only cut a log in half, but if you use a special frame, you can dissolve the log onto boards right in the forest.

Important! The band sawmill is considered the most efficient and cost effective.

Output

Sawing logs is considered one of the most difficult and important tasks in logging and lumber production. The quality of the products and the income of the enterprise depend on the chosen scheme, a well-designed work procedure and preparation of the tool.

The video in this article will tell you about the types of sawmills and how to cut wood.

Find out which part of the trunk is cutboards or timber it is possible by the pattern of tree rings, looking at their end, as well as by the number of knots on the boards or beams. The butt part of the trunk is always thicker than the top one and, as a rule, does not have branches, that is, it contains better quality wood.

The so-called technological wood raw material is obtained from the middle part of the whip - wood supplied to mechanical (for chipboard production, Fiberboard) or chemical (for example, for hydrolysis production) processing. The remaining butt part of the whip is cut into two or three parts, which are sent to the sawmills.

At sawmills, lumber is produced from logs, sawing them parallel to the longitudinal axis.

Among the sawn timber are distinguished:

timber (more than 100 mm wide and thick)

segmented beams or quarters (obtained from a log that is cut into quarters)

bars (up to 100 mm thick and no more than double thickness wide)

Boards (up to 100 mm thick, double thickness width)

obapol - lateral parts of the log

slats - thin boards and bars cut off during longitudinal sawing

In addition to the listed basic sawn timber, there are also so-called semi-finished products, in particular, grooved and profiled boards, plinths and other molded products.

The thickness of the boards emerging from the saw frame is determined by the distance between the saw frame blades

1 - a bar is cut from the heartwood of a log;
2 - when receiving half beams, the log is sawn along the longitudinal axis;
3 - when receiving segment beams, the log is cut crosswise along the longitudinal axis;
4 - for group sawing (wadding), unedged boards are obtained in one pass of a log through the sawmill frame;
5 - for individual sawing with a bar, at the first pass through the frame, a two-edged bar, slabs and side boards are obtained;
6 - the most difficult is radial sawing of a log, in whichfloorboards with vertical growth rings;
7 - in the second pass, the two-edged bar is turned 90 ° and cut into

Edged boards, separating the side wane from it;
8 - for boards with horizontally located growth rings, the front side is called the side facing the core (core), and the back is the side facing the sapwood (peripheral part of the trunk)

1. The outer layer of bark, which protects the tree from cold and heat, and therefore from intense evaporation of moisture.
2. Through the inner layer of bark (bast), the tree receives the necessary for its development nutrients... As the tree grows, the bast dies off, joining the outer layer of the bark.
3. Between the bast and the wood itself there is a cambium, which ensures the growth of the tree in thickness and the formation of annual rings.
4. Sapwood - external, a layer of active wood, adjacent to the cambium and feeding the tree with moisture. The older inner layers of sapwood gradually recede towards the heart.
5. The inner dead layers of wood, no longer fed by moisture, form a core (core), which, due to its strength, is the supporting and supporting core of the tree